Recently, as an autonomously moving robot, a mobile robot which autonomously moves, recognizing its external environment, is known. It is dangerous if the mobile robot collides with an obstacle. Therefore, for example, a technique is known in which a system for reducing the risk of a collision with an object during the movement of the mobile robot, as its specific operation, generates an environment map showing geometric conditions of the environment including the object, then compares data of the moving route through which the mobile robot moves with a coordinate system of the environment map, finds a risk parameter indicating the possibility of a collision with the object due to a control error during the movement of the mobile robot, and thereby avoids a collision with the obstacle in the movement environment. Such a technique is disclosed, for example, in JP-A-2009-291540.